The objective of this study is to identify the functional activity of regional lymph nodes, with respect to cell-mediated immunity to tumor-associated antigens, in patients with colorectal carcinoma. The responsiveness of regional node cells and peripheral blood lymphocytes to autologous and allogeneic tumor cells and/or extracts will be tested in lymphocyte stimulation and indirect leukocyte migration inhibition assays. Reactivity to cells and/or extracts from clinically uninvolved colon will be tested to assess specificity of any tumor reactivity; phytomitogens andd allogeneic lymphocytes will be used to test general immunocompetence. In addition to test of functional reactivity, an enumeration of proportions of E-rosette-forming cells (T-lymphocytes) and surface immunoglobulin cells (B-lymphocytes) will be made. The stimulation and migration indices, as well as T-and B-lymphocyte proportions of regional lymph nodes and peripheral blood will be correlated and evaluated with other relevant clinical and laboratory data.